The invention concerns a drilling resistance measuring device for material testing that is provided for work and use in humid environment, in particular also under water. The drilling resistance measuring device comprises a housing in which a drive and a drill chuck, coupled with the drive and provided with a drilling needle detachably arranged therein, are arranged, wherein the housing comprises a drilling needle outlet opening which is surrounded by a drilling needle outlet guide and through which the drilling needle extends out of the housing.
For performing drilling resistance measurements by means of which material properties in the interior of test bodies are derived, drilling resistance measuring devices with thin drilling tools or drilling needles are used. The drilling needle is moved by a drive of the drilling resistance measuring device and driven into the test body wherein, for example, the power input or the current consumption of the drive is used as a measure for the drilling resistance of the test body upon penetration or removal of the drilling needle and correlated, for example, with the penetration depth of the drilling needle so that the material properties in the interior of the test body can be assessed.
In case of measurements in humid environment, for example, in pouring rain or under water, penetration of moisture or water into the drilling resistance measuring device is to be prevented in order to avoid damaging the drive.
DE 100 31 334 A1 discloses in this context a drilling resistance measuring device that comprises an outlet opening for the drilling needle and means for generating an increased gas pressure in the interior of the drilling resistance measuring device so that the pressure present in the interior of the drilling resistance measuring device corresponds to a simultaneously measured outer pressure and no water can penetrate into the interior of the drilling resistance measuring device. The means for generating an increased inner gas pressure can be a pressurized gas line coupled with the interior of the drilling resistance measuring device or an attached gas cartridge.
Based on this prior art, it is the object of the present invention to provide a drilling resistance measuring device that is functioning in humid environment and under water independent of a pressurized gas source.